Bacteria

microorganism · single-celled · ancient life · everywhere

Tinier than tiny. Bacteria are so small you need a microscope to see them, usually just a few micrometres long. That means millions could fit on the head of a pin!

Found everywhere. Bacteria live in almost every habitat on Earth, from soil and water to the air we breathe, hot springs, and even deep inside Earth's crust. They were some of the first living things to appear on our planet billions of years ago.

Nature's recyclers. Bacteria break down dead plants and animals, returning nutrients back to the soil so new plants can grow. They also capture nitrogen from the air and turn it into something plants can use, which is why they're essential to all life on Earth.

Life around vents. In extreme places like hydrothermal vents on the ocean floor, special bacteria called extremophiles survive by converting chemicals like hydrogen sulphide into energy, feeding entire communities of creatures in the darkness.

Living together. Bacteria have different kinds of relationships with plants and animals, sometimes helping them, sometimes living alongside them without harm, and sometimes making them sick.